Scale Aircraft Engines

[dave_t]

I found this photo on one of the Japanese solid modeling sites. A pair of scratch built radial engines for a Junkers Ju-88. No details given, but it looks like maybe wire wrapped around each cylinder core. I believe they are 1:48th scale.

For a larger image...
http://saiunkai.s261.xrea.com/cgi-main/img-box/img20090614085015.jpg

[lastvautour]

They look great.

Lou

[R.F.Bennett]

I have seen this same technique on some of the old plans and build articles. Only they would use string wrapped around a wooden dowel. A coil spring might work well too. Tension, not compression. In some of the same plans sewing pins were used for pushrod tubes and bolt heads. Might be an interesting group build.
A simple Radial engine, large scale say 1/32.

[Paul]

It might be fun to build a Clerget or Le Rhone.  I assume a rotary engine can be considered a variety of radial? I'm in.   Maybe I'll even stick an airplane to the back end of it.

[lastvautour]

A 1/32 radial would do nicely in my WACO Cabin Biplane. It has been on shelf for almost a year now. I have the wings rough cut and a block for the fuselage. I am experimenting with showing the fabric covered wings.

Lou
I have some radial engine line drawings somewhere in the basement. I will list what I have tomorrow.

[R.F.Bennett]

I have some good Wylam drawings but you'll have to give me a week to scan and post them. It's a P&W Twin Wasp JR.

[lastvautour]

I have Wylam drawings for the Cyclone F-50, Wright Whirlwind, P & W Wasp Jr and the Clerget. I will be looking for some info on the Jacobs 750HP seven cylinder engine for my 1/32 Waco Cabin Biplane. My wings are rough cut already and I will be making a second fuselage to replace the one I screwed up this morning. You know measure twin, cut one !!!!!!! Sorry no rotary engines.

Lou

[R.F.Bennett]

I would like to amend this too include any Air Cooled Aircraft engine. The reason being that there are so few good drawings of these subjects available and such variation in detail and technique that I believe we would be mistaken to exclude such interesting any power plans layouts that can offer a learning experience to all of us. I propose we include Rotary, Inline, Opposed and V engines in this build, as long as they are AIR cooled. This opens the field to include engines such as Liberty, Mercedes, Lycoming and Continental ect. This opens the door to include sister builds of WATER cooled and JET engines in the future.
Does any one second this?

[lastvautour]

Works for me Ray.

Lou

[Paul]

Found some beautiful renderings of a LeRhone 110hp:

http://www.theaerodrome.com/forum/aircraft/14397-le-rhone-oberursel-engine-blueprints.html

[R.F.Bennett]

This build has been proposed, seconded and approved. It has been amended to include all AIR cooled aircraft engines.
This build has no expiration date.
Let the chips fly Gentlemen! 

[lastvautour]

I always start my engines by making a cylinder locator. In this case the engines are nine cylinder so the locator has 40 degrees per sector. The crankcase is 8mm in diameter and cylinders will be 1cm in height
http://smm.solidmodelmemories.net/Gallery/displayimage.php?album=241&pos=4

Lou

[lastvautour]

The cylinder location is transferred to the other end of the dowel using a strip of paper. followed by marking the location in reference to the end of the crankcase.
http://smm.solidmodelmemories.net/Gallery/displayimage.php?pos=-3414

[lastvautour]

Rotate the dowel as to mark the location of the cylinders and any shaping required to form the crankcase.

Locate the centre of the dowel and drill the prop shaft before shaping the crankcase

Start a pilot hole and then enlarge to the diameter of the peg used to attach the cylinder. I use round toothpicks

I recommend that the cylinder locations be drilled prior to shaping the crankcase. I had some problems with the wood splitting slightly when drilling on my first crankcase.

Enlarged picture can be found at http://smm.solidmodelmemories.net/Gallery/thumbnails.php?album=241

[lastvautour]

I have two method of attaching the cylinders to the crankcase. The first is to reduce the diameter of the cylinder to fit 5/64" hole(toothpick diameter) and the other is to hollow out the cylinder to accept a round toothpick.
Either way works fine.

http://smm.solidmodelmemories.net/Gallery/displayimage.php?pos=-3433 In trying to resolve the simulation of the cylinder fins, I used a known method and a bit of a twist. I used telephone wiring for its size and bared 3" of wire. Wrap the wire around the cylinder and there you go. I found it was easier to wrap around a long section of dowel, cut and bore out the end and attach with a toothpick insert. This was kind of trial and error until I got the wrap nice and tight.

http://smm.solidmodelmemories.net/Gallery/displayimage.php?album=241&pos=11Note that the silver cylinder has little definition. I dipped the entire cylinder in paint and let dry before painting silver. Bad choice as the paint was way to thick and lost the fin effect. It will be replaced as it is only stuck to a toothpick.  More to come